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Continued: Cancer screening: How can a test be bad?

  • Article by: MAURA LERNER , Star Tribune
  • Last update: October 30, 2011 - 9:09 PM

For years, Dr. Donald Layton made a point of urging other men to get screened for prostate cancer. A retired Mayo Clinic physician and prostate-cancer survivor, he was convinced the test was a lifesaver.

But about a year ago, he had a change of heart.

Today, he believes there's no reason for otherwise healthy men to go looking for trouble. "I stopped going out saying everybody should be tested," said Layton, 83.

Layton has joined a growing chorus of skeptics who believe too much testing has led to an epidemic of over-diagnosis and over-treatment.

This month, the U.S. Preventive Services Task Force said there's no evidence that routine PSA (prostate-specific antigen) testing saves lives. For the vast majority of men, the panel said, it may cause more harm than good. And last Monday, a study by Dartmouth College cast fresh doubt on the value of mammograms in fighting breast cancer.

Their concern: that doctors end up conducting search-and-destroy missions for cancer cells that pose no real danger to patients, and that for many people, the cure is worse than the disease.

It's a message that has infuriated some advocates and physicians, while creating uncertainty for patients and their families.

"Right now, there's a lot of people that are giving recommendations for screening; one of the difficulties is that they don't always agree," said Dr. Lorre Ochs, a Park Nicollet cancer specialist and president-elect of the Minnesota Society for Clinical Oncology.

Forced to rethink

"I think it does make it hard for patients when medical experts are really coming from completely different places," Ochs said.

Dr. Timothy Wilt, one of two Minnesotans on the Preventive Services Task Force, which advises the government on screening practices, readily admits that the new PSA draft guidelines may seem to defy logic. How can a test be bad?

"Every test we do in medicine has the potential for a benefit and a potential for a harm," said Wilt, a physician at the Minneapolis VA Medical Center.

In this case, Wilt said, the research found no real benefit: men who have PSA tests live no longer than those who don't. They may discover more cancer and have more treatment; but there's no advantage in survival rates.

"Sometimes the science supports exactly what we had hoped, and sometimes it forces us to rethink," Wilt said.

Basically, the research shows that most of the cancers found as a result of PSA tests are not life-threatening, Wilt said. But once the cancer is found, it's almost always treated -- with a considerable risk of side effects. As many as one-third of men are left impotent or incontinent, and 1 in 200 die from complications of surgery. With that in mind, the task force concluded that the risks of routine PSA testing -- on men with no symptoms -- outweigh the benefits.

"Cancer creates a very fearful image," said Wilt. "Fortunately, not all cancers are deadly, even if not treated."

Why wait?

The new draft guidelines on PSA testing, released Oct. 11, prompted a swift backlash. The American Urological Association, whose members treat prostate cancer, issued a statement accusing Wilt and his colleagues of "doing a great disservice to the men worldwide" by disparaging the test.

While conceding that "not all prostate cancers require active treatment," the statement said: "We are concerned that the Task Force's recommendations will ultimately do more harm than good to the many men at risk for prostate cancer."

A similar backlash followed the task force's 2009 breast cancer guidelines, which advised against routine mammograms for women under 50.

To many, it's puzzling to think that anyone might be better off waiting until symptoms appear, when it may be too late for treatment.

If the cancer is aggressive, everyone agrees that early diagnosis and treatment is best, said Dr. George Isham, chief health officer at HealthPartners, who also serves on the federal task force.

The problem, he said, is that it's often impossible to distinguish between the harmless and the deadly.

"In prostate, we happen to know that the majority of these cancers are fairly slow growing and in fact won't kill them," Isham said. "Some, unfortunately, are very aggressive and lethal, and the problem is in sorting between those different types." The tests cannot always make the distinction, he said, and that's the take-home message.

Tough call

Layton said his own reaction was "pretty typical" when he discovered, as a result of PSA testing, that he had cancer 20 years ago.

"I wanted it out of there," said Layton, who was a neurologist at the Mayo Clinic. After he recovered, he joined a Rochester support group for prostate cancer survivors and went on the road promoting PSA tests at men's clubs and church groups.

Now, he says, he thinks that could be a mistake, considering the side effects from potentially needless treatment. "You're going to be giving curative treatment to a lot of people, at great expense, who will die of something else and never have symptoms," he said.

Richard Vetter, a retired Mayo Clinic scientist who is also in the Rochester support group, says the debate has caused anxiety for some fellow survivors. "They're dealing with a significant quality-of-life issue, and they're wondering if they made the right decision," he said.

But personally, he has no regrets about the PSA test. "The point is, it's the best we have," he said. "You don't want to take a chance. I have to believe that it did save my life."

Ochs, the Park Nicollet oncologist, says it can be a tough call for patients and doctors alike.

"It's so counterintuitive. Why wouldn't it be good to know?" she said. "Why wouldn't you want to do something about it? But there are circumstances where we probably don't change the outcome by doing something about it.

"But I think that's a hard sell to the public."

Maura Lerner • 612-673-7384

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